1. Field of the Invention
The present invention relates to a projection apparatus, and more particularly, to an illumination module for adjusting a position of a luminous element of a projection apparatus and a method for adjusting the brightness of a projection frame of the projection apparatus.
2. Descriptions of the Related Art
Nowadays, projection apparatuses have found a wide application in various business conferences, home theaters and the like. As shown in FIG. 1, there is an illumination module 2 of a conventional projection apparatus 1. The illumination module 2 has a light source 21, an integration rod 22, a plurality of optical elements 23 and a digital micromirror device (DMD) 24. A light ray is emitted from the light source 21, homogenized by the integration rod 22 into an almost parallel light, then refracted by the optical elements 23 into the digital micromirror device 24 to be combined with an image input signal, and finally reflected from the digital micromirror device 24 to form a projection frame of the projection apparatus 1.
However, during the actual assembly process of the illumination module 2 of the conventional projection apparatus 1, it is often impossible for the light source 21, the integration rod 22, the optical elements 23 and the digital micromirror device 24 to be aligned exactly, resulting in an offset of the position of the light source 21. This makes it impossible for the light source 21 to project all the light rays to the integration rod 22 at a preferred position, thereby affecting the brightness of the projection frame thereof.
To solve the aforesaid problem, after the conventional projection apparatus 1 is assembled, a plurality of brightness sensors are usually provided around a projection screen to detect the brightness of the projection frame projected by the projection apparatus 1, and the light source 21 is manually adjusted to an optimal position so that all the light rays of the light source 21 are emitted to the integration rod 22. However, this kind of manual calibration is not only time- and labor-consuming but also fails to achieve a completely accurate alignment. Moreover, if an offset of positions of such elements as the light source 21 and the integration rod 22 takes place after some internal part of the projection apparatus 1 is replaced by a user, then the user who has no professional equipment, such as a brightness sensor, will be unable to instantly adjust the positions, leading to a significantly decreased imaging quality of the projection apparatus 1.
In view of this, an urgent need exists in the art to develop a technology for automatically adjusting a position of a light source to effectively adjust the brightness of a projection frame of a projection apparatus and to overcome shortcomings of complexity in the adjusting procedure and difficulty in the process control.